My car's been doing this for a while. Here's a senerio, I will have the car on cruise control on the 401 and when I get to a slight hill my vacuum decreases (as it should) and all of a sudden knock, 10, 20, 30, 43 pegged. And I'll just ignore it, 15 seconds later on the same incline, same throttle position, knock will go back to 0. I have decresed the fuel by as much as 10% and richened it by as much as 20% with my S-AFC with no results. My O2's are just on the rich side of oscilating. I am talking VERY small inclines here where I am still have like 7inHg.

In boost, 22psi with a Big 16g I get about 34 knock, less than cruising

I have some logs I can send to people, just ask. You'd use plviewer to see them. Any idea what the heck is going on here? I use 93 octane for these tests by the way. I normally don't care but at times I can't cruise at 100kph no matter how slow I try to get there because I am pegged at 43 knock and have 7 degrees of timing.

TIA.

Wes,

Try reducing your base timing to 5 degrees, and see if this helps to reduce the amount of knock. Before you rack your brain with possibilities, you may want to try a different sensor, just to eliminate the possibility that yours is flaky.

Can you hear the knock? I was experiencing similar problems on my last motor, and it turned out to be a worn rod bearing, which then failed catastrophically.

My base timing is 5 degrees, as it should be. I've tried another knock sensor with the exact same results. I can't hear any knock whatsoever at any points in time. It's a JDM motor with a lot of kms on it since I put it in but it runs really good.

Sometimes, if you get off the gas, and get back on it will not knock so bad. If I want to get a little pull then I will roll into it and if the timing gets pulled (TMO ECU, boost guage acts as timing) I don't go, but it it doesn't, I'll get on the gas and it hauls ass.

I am going to try another ECU I think. Anyone know the signs of a bad fuel filter? Those are the only things I can think of now.

You got the same problem as me Wes, does your EGT temp climb up to 860c or so when its knocking like this? mine does, then goes back to normal...the car also seems to bogg down too cause of the retarded timing.
I'm also getting part throttle knock when just driving in the city, not always tho.
In my case at least it seems to be the lifters, I'm getting the revised ones soon. I too tried adjusting my fuel trims, at about 100% now, all that and still its the same.
Are your lifters noisey at all? What i did was put in some STP oil treatment and its suppose to stop lifter tick for a short time just so you can diagnose it. I did that and my lifter tick went away as did my knock...only lasted a day tho.

I don't have EGT. I get it driving around town too, I can be pulling away from a light and in 2nd gear I have full knock. If it was lifters wouldn't it be all the time though, or more RPM dependent rather than load dependent? I have 1 noisy lifter that I can only hear for about 2 mins a week and it goes away when warmed up. 99% of the time all you can hear are the injectors firing. I cna try the oil treatment, but can you hear your lifters, cause I can't.

I have the exact same thing with my car.

Knock in 1st & 2nd and part throttle knock. Sometimes if I get lucky and get off, then on the gas (like Wes) the car hauls out.

I have the new lifters and a brand new knock sensor. Timing is set to 5 degrees. EGT's do not get that high (about 1450°F).

I'm wondering if it's at least partially EGR related since mine is not functional.

Seems I am not alone here. I have a JDM cyclone intake -> No EGR.

What I have to wonder is (since I don't have EGT) if the high EGT's are causing the knock, or if knock is pulling timing causing the high EGT's. To find the problem we need to know which came first, the chicken or the egg?

Welcome to the club. In my case, I am fairly certain it's the lifters. When this happens, I can hear them clacking away. What I find usually works to silence them is a couple of good revs to high rpms and the chatter and 'knock' dissappears... for a while.

I used to have your exact problem, Wes. Thankfully, I don't have it anymore....

Its usually not lifters. I had the noisiest lifters which since were replaced with quiet ones. That did not stop the part throttle knock.

Several things cause part throttle knock. Incorrect timing, incorrect fuel, and dirty combustion chambers.

Try a systematic approach, and attempt to eliminate each possible cause one at a time.

I would suggest starting with backing your base timing in 1 degree increments. Then drive around with the datalogger. Take notes.

I'm sure you're thinking,"Back off my base timing? But I'll loose power!". Well, the ECU is the main timing controller, and by backing off your base by 1 degree (assuming thats all it takes), by not having knock your ECU can now advance your timing 5, 10 ,15 or more degrees.....

If you've got your base timing to zero, and you still have the same knock, then it would be a sure bet its not timing.

I kinda doubt your fuel trim is a cause, as you've already played around with that. Some of your part throttle knock might even be occurring in closed loop, meaning that adjusting the afc will be ineffective because the ECU will still be controlling fuel delivery base on o2 feedback,etc.

That would leave dirty combustion chambers. Pull the head, get a valve job, and kiss goodbye to part throttle knock.

You may not be able to hear the lifters, but they are still ticking. If they tick at a certain frequency they will mimick a knock signal and the ks will go off, so that means they may be ticking very loud, but the frequency is not like a knock frequency so the ks doesn't pick it up. I usually get it from 2700-3400rpm.
I'm getting the new lifters by next week hopefully, I'll post the results.

I myself have done most of the checks, timing is set right, but i did not try to pull the timing back at all like Chris suggested, combustion chamber is clean, new plugs and wires, and the old plugs looked fine, no sign of knock.

Its also been mentioned before that worn rod bearings can cause the ks to go off.
As for the EGR, I recently blocked mine off, but how could a blocked off EGR cause this, or even a malfunctioning one?

By design, the EGR system reduces combustion chamber temperatures during part throttle conditions to reduce the production of Oxides of Nitrogen (Nox). It achieves this by polluting the intake air with gases that have already been burned.

If the EGR system is disabled, the intake air is not polluted and combustion chamber temps should be higher (all else being equal). This can lead to knock, I've seen it in other cars. I haven't done any testing on the Laser yet though. The ECU may tune out some of the effect in the fuel trims but I don't think it can do it completely.

I still have to do some digging on the DSM EGR system. I'll take a look at the Tech Manual.

Dirty combustion chambers or piston tops can cause knock too (as Chris says). Combustion chamber cleaning fluid may not get it all off as sometimes the crap is baked rock solid.

EGR's recirculate hot exhaust gasses into a nice cool intake charge. I'd say they heat it up when they polute it. That is why most people block them off. It cools the intake charge.

My aircare readings were very good even with it blocked off.

I assume the AirCare test is the same as the DriveClean test in Ontario. If so, your EGR system wasn't tested. The EGR system can only be tested with the car on the dyno.

The main reason I know of that people block off the EGR valve is to reduce the carbon deposits inside the intake manifold. The EGR system doen't operate during WOT (to my knowledge) so heating the intake air doesn't happen when you're looking for max HP.

we get dynoed here

all good.

but good info on the non-WOT operation.

however, we are talking about part throttle, no??

I would think that cooling down the intake charge has to be good for just about every normal driving condition.

Damn, they have 4 wheel dynos for the emissions test in BC?
Are the test limits set pretty high?

Yup, we are talking about part throttle.

I guess it could be considered good if you're not worried about the generation of NOx. The EGR system doesn't really hurt the performance of the car (except for the carbon deposits). The trouble is, the car was designed to have it. This means the fuel curve in the ECU is probably tailored to suit the needs of an engine with an EGR valve.
If that's true, then it's possible that a malfunctioning EGR system could lead to part throttle knock. Actually, I've seen it first hand.

So the conclusion is that it's the EGR system? I am going to try a few other things however if that's what it is, how does a guy like me (with no EGR at all due to the JDM manifold) get away from this problem. You'd think everyone with a blockoff plate would HATE this problem.

Wes

The jury is still out. In my mind, it is a contributing factor.
I'm sure there are cars out there with no knock at all (and no EGR). I'd be curious to know if those cars are running a completely stock fuel system or if things have been richened up enough to eliminate knock.

I suspect that dirty combustion chambers and a blocked EGR would be a recipe for knock.

I have switched to BPR7ES plugs and using Sunoco 94, I still get part throttle knock. It's not as bad as it was though. The car knocks cold or hot, though it is a bit worse when hot.

Do you have a clean fuel filter in your car, Rob? How about a vented BOV? (Mine is vented and crushed) Hacked MAF? (I have an unhacked 2G)

I'd have no way to tell if the combustion chamber is dirty, never knew it really happened badly as I have seen it on valves but not really in a cylinder.

I NEED to get rid of this.

I have a brand new Fram HPG-1 fuel filter (Fram Filter) , fuel delivery shouldn't be a problem. I have a Walbro 255HP as well.

BOV is not vented or crushed. Fuel and air intake systems are pretty close to stock.
Here's the rest:
1G MAS, unhacked
450 injectors
hacked aircan (K&N filter)
small 16G
Aeromotive FPR
stock boost control solenoid (no MBC)

I'd like to get rid of mine too.

I find that when I launch with the stutterbox, I don't have knock.

I don't knock about ~3700 unless I am right on it and have the boost turned up and happened to not have 94 in the tank. I could drive at 4500 all day and not have this problem.

Sounds like between the two of us it's the SAME problem, with no fix?

Rob, do you have balance shafts? I notice that neither Ryan or myself do.

I am experiencing the same problem.

I have no balance shaft either. Please tell me I do not have to live with part throttle knock cause of this.